Laser pointer discussion. Read/write reviews of laser pointers and laser pointer companies. Learn about all types of laser pointers and lasers





Welcome to Laser Pointer Forums! If you are looking for a laser pointer or want to compare different laser pointer companies, you may want to check out the LPF Laser Pointer Company Database. The link will open in a new window for your convenience.








Green Laser Pointers by Category Blue Laser Pointers by Category Red Laser Pointers by Category
Yellow Laser Pointers by Category Violet Laser Pointers by Category Orange Laser Pointers by Category
Top Laser Pointers by Power - 1 Watt+ Top Laser Pointers by Power - 500mW+ Top Laser Pointers by Power - 250mW+
Laser Pointer Database High Power Laser Pointers Laser Pointer Diodes
Laser Technology Laser Pointer Parts Lasers by Wavelength
Top 10 Laser Pointer Companies Laser Pointer Company Database Visible Beam Laser Pointers


One laser store meets all your needs

























Go Back   Laser Pointer Forums - Discuss Laser Pointers > Lasers > Blue, Yellow, & Other Colored Lasers



LPF List of Laser Pointer Companies (link opens new window)



Closed Thread
 
LinkBack Thread Tools Display Modes
Old 05-06-2011, 09:54 AM #1
rhd's Avatar
rhd rhd is offline
Class 4 Laser
 
Join Date: Dec 2010
Posts: 8,491
Rep Power: 1392
rhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond repute
rhd rhd is offline
Class 4 Laser
rhd's Avatar
 
Join Date: Dec 2010
Posts: 8,491
Rep Power: 1392
rhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond repute
Default Why can't we frequency double 1208nm ?

I just finished reading goninanbl00d's DPSS primer. One of the more useful threads/primers I've read in a while actually - I found it quite well layed out and straightforward.

However, I'm still not entirely clear as to why we can't frequency double some other wavelengths apart from 1064. For example, why could we not use KTP to frequency double a 1206nm diode like this one to end up with a fairly unique 604nm orange colour?

This seems too simplistic, but I've heard that Corning had some green 530 (?) nm lasers that were really just 1060nm diodes, directly doubled (as opposed to traditional 808 pumped DPSS). They're used in some of the ShowWX pico projectors. The fact that I haven't seen this done anywhere, is enough to suggest to me that it isn't that simple. I'm presuming that KTP can't simply double anything you throw at it. However, I'm also somewhat left with the impression from that DPSS primer that KTP can double anything above 500nm.


__________________
CURRENT WAVELENGTHS:
405|441|450|467|473|495|505|520|532|556|PGLRG|589|594|632|638|660


SAFETY & IMPORTANT READING (threads authored and contributed to by various members of LPF):
- Federal Aviation Administration - Laser Safety Initiative (link)
- Info release from Laserglow - Default Canadian restrictions on portable lasers (link)
- The Necessity of Safety Goggles (link)


Last edited by rhd; 05-06-2011 at 09:56 AM.
rhd is offline  







LPF List of Laser Pointer Companies (link opens new window)







Old 05-06-2011, 10:00 AM #2
LORDJET's Avatar
Class 2 Laser
 
Join Date: Oct 2010
Location: North Carolina
Posts: 278
Rep Power: 16
LORDJET is a splendid one to beholdLORDJET is a splendid one to beholdLORDJET is a splendid one to beholdLORDJET is a splendid one to beholdLORDJET is a splendid one to beholdLORDJET is a splendid one to beholdLORDJET is a splendid one to behold
LORDJET LORDJET is offline
Class 2 Laser
LORDJET's Avatar
 
Join Date: Oct 2010
Location: North Carolina
Posts: 278
Rep Power: 16
LORDJET is a splendid one to beholdLORDJET is a splendid one to beholdLORDJET is a splendid one to beholdLORDJET is a splendid one to beholdLORDJET is a splendid one to beholdLORDJET is a splendid one to beholdLORDJET is a splendid one to behold
Default Re: Why can't we frequency double 1208nm ?

Or perhaps there is some other kind of SHG crystal that could be used? May not be cheap though.
__________________
Your focus determines your reality.
LORDJET is offline  
Old 05-06-2011, 10:06 AM #3
rhd's Avatar
rhd rhd is offline
Class 4 Laser
 
Join Date: Dec 2010
Posts: 8,491
Rep Power: 1392
rhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond repute
rhd rhd is offline
Class 4 Laser
rhd's Avatar
 
Join Date: Dec 2010
Posts: 8,491
Rep Power: 1392
rhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond repute
Default Re: Why can't we frequency double 1208nm ?

I'm sure it wouldn't be cheap. That diode alone is listed at $700 (although thorlabs seems to be about 2x the competitive price of elsewhere on diodes). But if people spend three digits (nearly four) on 589, I'm sure they would on 604?
__________________
CURRENT WAVELENGTHS:
405|441|450|467|473|495|505|520|532|556|PGLRG|589|594|632|638|660


SAFETY & IMPORTANT READING (threads authored and contributed to by various members of LPF):
- Federal Aviation Administration - Laser Safety Initiative (link)
- Info release from Laserglow - Default Canadian restrictions on portable lasers (link)
- The Necessity of Safety Goggles (link)

rhd is offline  
Old 05-06-2011, 10:36 AM #4
goninanbl00d's Avatar
Class 2M Laser
 
Join Date: Jun 2010
Location: Sydney, AU
Posts: 892
Rep Power: 97
goninanbl00d has a reputation beyond reputegoninanbl00d has a reputation beyond reputegoninanbl00d has a reputation beyond reputegoninanbl00d has a reputation beyond reputegoninanbl00d has a reputation beyond reputegoninanbl00d has a reputation beyond reputegoninanbl00d has a reputation beyond reputegoninanbl00d has a reputation beyond reputegoninanbl00d has a reputation beyond reputegoninanbl00d has a reputation beyond reputegoninanbl00d has a reputation beyond repute
goninanbl00d goninanbl00d is offline
Class 2M Laser
goninanbl00d's Avatar
 
Join Date: Jun 2010
Location: Sydney, AU
Posts: 892
Rep Power: 97
goninanbl00d has a reputation beyond reputegoninanbl00d has a reputation beyond reputegoninanbl00d has a reputation beyond reputegoninanbl00d has a reputation beyond reputegoninanbl00d has a reputation beyond reputegoninanbl00d has a reputation beyond reputegoninanbl00d has a reputation beyond reputegoninanbl00d has a reputation beyond reputegoninanbl00d has a reputation beyond reputegoninanbl00d has a reputation beyond reputegoninanbl00d has a reputation beyond repute
Default Re: Why can't we frequency double 1208nm ?

Quote:
Originally Posted by rhd View Post
I just finished reading goninanbl00d's DPSS primer. One of the more useful threads/primers I've read in a while actually - I found it quite well layed out and straightforward.

However, I'm still not entirely clear as to why we can't frequency double some other wavelengths apart from 1064. For example, why could we not use KTP to frequency double a 1206nm diode like this one to end up with a fairly unique 604nm orange colour?

This seems too simplistic, but I've heard that Corning had some green 530 (?) nm lasers that were really just 1060nm diodes, directly doubled (as opposed to traditional 808 pumped DPSS). They're used in some of the ShowWX pico projectors. The fact that I haven't seen this done anywhere, is enough to suggest to me that it isn't that simple. I'm presuming that KTP can't simply double anything you throw at it. However, I'm also somewhat left with the impression from that DPSS primer that KTP can double anything above 500nm.
Thanks.

As I've said before about KTP and 'throwing photons KTP with a diode for them to shit out a stream of photons out the other end', it isn't a very straightforward process. Finding the correct wavelength is only the start of it.

First off, due to a property inherent to KTP, it cannot double well below 500nm, and not all in the blue, as it cannot be phase-matched for those wavelengths. This same property allows it to double 1064nm with such brutal efficiency.

KTP is also used in the SHG of 1319 and 1342 for 660 and 671nm respectively (both are Nd:YAG/YVO4 lines). It's also used in SFG (sum frequency generation) for both 589 and 594.5nm.

The second issue that comes to mind is power density- and although it may seem easy to get plenty of power (5W in a C-mount 808 is easy to get), cramming that power into something that is usable is not nearly as easy.

First off, although 3W (like in the diode you linked) may seem like a lot of power, bear a few things in mind:

1. Being a multimode, multi-emitter device, the output beam will be very messy, not to mention extremely astigmatic.
2. There'll be no easy way to focus that down to the spot size needed for effective SHG.

To put things into perspective, your dinky little 5mW green pen laser has watts of power circulating through the cavity at any given time. Only a small percentage ever makes it out as 532nm, of course, and most of that power remains in the cavity.

The other thing about said dinky pen laser is that the intracavity 1064nm beam is often micrometers wide. Without a FAC, the intracavity beam is usually slightly smaller than diode's active emitting area, while with a FAC, the intracavity 1064 is often narrower.

So, you have many watts of power in a tiny spot. SHG, being a non-linear process, works better almost exponentially as power levels rise.

Put those two together, and you'll see that sending a single diode for a pass through a doubling crystal won't work.

Case-in-point: An SSY-1 (flashlamp-pumped pulsed Nd:YAG laser with a nominal peak power of 200mJ) has trouble achieving green output when it is shot through a KTP crystal. The same laser with a passive Q-switch (which serves to increase the peak power) has no problem with extracavity doubling. Without the Q-switch, the power is on the order of kW, while with the Q-switch, it rises to hundreds of kW (or even into the MW range if pumped correctly).

Of course, with the diode being multimode and mult-emitter, getting it to the point size necessary is extremely difficult. And even if you do manage to break a handful of the laws of physics and pull it off, it'll be an even bigger challenge to contain it within the doubling crystal.

On top of that, the diode has to be phase-matched with the doubler crystal. Due to the beam profile and astigmatism involved often this can't be done with a diode.

When you have seen a directly-doubled diode (such as the Novalux Protera 488 series), they use a special external-cavity VESCEL diode. The VESCEL diode design eliminates the astigmatism and poor beam profile inherent to normal diodes, while the external-cavity design means that the doubling optic is also part of the cavity, giving the power densities needed. Phase-matching can then be achieved, and a TEC is used to stabilise the doubling crystal and the diode to ensure temperature fluctuations do not result in an un-phase-matching of the setup.

It's far from easy, however, it can be done. It's also very expensive, and often, it's easier to just go DPSS instead of messing around with doubling of a diode. Sure, laser diodes scale well in terms of power, but by the time you hit multi-mode multi-emitter devices, it's near damn impossible to use the output for anything but pumping another laser (or burning stuff, if you're into that).
goninanbl00d is offline  
Old 05-06-2011, 01:15 PM #5
Trevor's Avatar
Class 3B Laser
 
Join Date: Jul 2009
Location: Boulder, CO
Posts: 4,506
Rep Power: 2565
Trevor has a reputation beyond reputeTrevor has a reputation beyond reputeTrevor has a reputation beyond reputeTrevor has a reputation beyond reputeTrevor has a reputation beyond reputeTrevor has a reputation beyond reputeTrevor has a reputation beyond reputeTrevor has a reputation beyond reputeTrevor has a reputation beyond reputeTrevor has a reputation beyond reputeTrevor has a reputation beyond repute
Trevor Trevor is offline
Class 3B Laser
Trevor's Avatar
 
Join Date: Jul 2009
Location: Boulder, CO
Posts: 4,506
Rep Power: 2565
Trevor has a reputation beyond reputeTrevor has a reputation beyond reputeTrevor has a reputation beyond reputeTrevor has a reputation beyond reputeTrevor has a reputation beyond reputeTrevor has a reputation beyond reputeTrevor has a reputation beyond reputeTrevor has a reputation beyond reputeTrevor has a reputation beyond reputeTrevor has a reputation beyond reputeTrevor has a reputation beyond repute
Default Re: Why can't we frequency double 1208nm ?

Well, if you could somehow SFG 1319nm and 1112nm you would get 603.3nm...

-Trevor
__________________
Code:
23:10 <ARG>    nothing has blown up yet :)
23:10 <Trevor> that is a distressingly low standard for success
Trevor is offline  
Old 08-28-2012, 12:27 PM #6
Junior Member
 
Join Date: Aug 2012
Posts: 1
Rep Power: 0
alsh is on a distinguished road
alsh alsh is offline
Junior Member
 
Join Date: Aug 2012
Posts: 1
Rep Power: 0
alsh is on a distinguished road
Default Re: Why can't we frequency double 1208nm ?

Hallo,
I'm appologizing a bit for some advertisment, but would like to point out that we are offfering 7W @ 1210nm multimode and 350mW (100pm FWHM) ex fiber for single mode.
But I would agree that goninanbl00d that multimode is not a desired dource for SHG.

Anyhow, from our single mode BTF it is possible to get up to 70mW of doubled light.

We are providing any wavelength for visible SHG. Even some of them with more power.
alsh is offline  
Old 08-28-2012, 08:39 PM #7
Class 1M Laser
 
Join Date: Oct 2011
Posts: 162
Rep Power: 8
flare09 has a spectacular aura aboutflare09 has a spectacular aura aboutflare09 has a spectacular aura about
flare09 flare09 is offline
Class 1M Laser
 
Join Date: Oct 2011
Posts: 162
Rep Power: 8
flare09 has a spectacular aura aboutflare09 has a spectacular aura aboutflare09 has a spectacular aura about
Default Re: Why can't we frequency double 1208nm ?

So is it possible, just an idea, that the crystals react to light the same way a tube would on a chime? Like there are some materials that vibrate at certain sound frequencies and will vibrate at each harmonic.

Is it the crystals vibrating at a specific light frequency in reaction to the incoming light, and changing the input to match those higher harmonics also lowers the response, just like trying to get a higher note out of a tube?
flare09 is offline  
Old 08-28-2012, 11:30 PM #8
Meatball's Avatar
Class 3B Laser
 
Join Date: Feb 2008
Location: Lincoln, NE
Posts: 2,989
Rep Power: 242
Meatball has a reputation beyond reputeMeatball has a reputation beyond reputeMeatball has a reputation beyond reputeMeatball has a reputation beyond reputeMeatball has a reputation beyond reputeMeatball has a reputation beyond reputeMeatball has a reputation beyond reputeMeatball has a reputation beyond reputeMeatball has a reputation beyond reputeMeatball has a reputation beyond reputeMeatball has a reputation beyond repute
Meatball Meatball is offline
Class 3B Laser
Meatball's Avatar
 
Join Date: Feb 2008
Location: Lincoln, NE
Posts: 2,989
Rep Power: 242
Meatball has a reputation beyond reputeMeatball has a reputation beyond reputeMeatball has a reputation beyond reputeMeatball has a reputation beyond reputeMeatball has a reputation beyond reputeMeatball has a reputation beyond reputeMeatball has a reputation beyond reputeMeatball has a reputation beyond reputeMeatball has a reputation beyond reputeMeatball has a reputation beyond reputeMeatball has a reputation beyond repute
Default Re: Why can't we frequency double 1208nm ?

PM sent to answer. Lets keep off the dead threads.
__________________
FIAT LUX

(\__/)
(='.'=)
(")_(")
Meatball is offline  
Closed Thread





Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On











Loading








Green Laser Pointers by Category Blue Laser Pointers by Category Red Laser Pointers by Category
Yellow Laser Pointers by Category Violet Laser Pointers by Category Orange Laser Pointers by Category
Top Laser Pointers by Power - 1 Watt+ Top Laser Pointers by Power - 500mW+ Top Laser Pointers by Power - 250mW+
Laser Pointer Database High Power Laser Pointers Laser Pointer Diodes






Privacy Policy | Advertising Disclaimer | Terms of Use


 


All times are GMT. The time now is 02:11 PM.


Powered by: vBulletin
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.
Search Engine Friendly URLs by vBSEO
Privacy Policy | Advertising Disclaimer | Terms of Use
Copyright (C) 2017 Laser Pointer Forums, LLC